With far too little water in some places and far too much in others, U.S. governments can no longer ignore climate change.

For me, the problem with water has gotten personal. Along with other fishermen last fall in northwest Michigan (where my wife and I live part of the year), I watched in near-horror as thousands of salmon struggled to swim up the Betsie River to spawn, only to beach themselves on sand bars because the water levels were so low -- almost three feet below normal. The state’s Department of Natural Resources closed down a number of popular fishing areas and started dredging canals near the mouths of some rivers in an effort to allow the fish to swim upriver.

This fall, the good news is that things should be much better, thanks to a very cold winter that froze over the lake for the first time in decades -- reducing evaporation -- and a snowfall that was 40 to 50 inches above normal.

In another place I care about, the outlook is not so positive. My brothers and I own a section of our mother’s family farm in central Kansas that has provided us with a little extra income, especially as prices for wheat and corn have risen in recent years. But our cousin, who does the farming, is warning that the Ogallala Aquifer underneath our land is running out of water. The aquifer, which runs from South Dakota and Wyoming down to the Texas Panhandle and New Mexico, yields 30 percent of the nation’s irrigated groundwater. In 2011, Kansas farms alone pumped 1.3 trillion gallons from the Ogallala, more than enough to fill Lake Okeechobee in Florida. But unlike Lake Michigan, one season of above-average snowfall isn’t enough to replenish the aquifer -- it’ll take many hundreds of years to recharge itself.

The problem in the Midwest is only now becoming apparent in the wake of a two-year drought. But in the West, lower-than-normal precipitation has been ongoing for 14 years. The slow-motion collapse of the Colorado River water system dwarfs all other threats to agriculture and population centers: It threatens a fast-growing area of 40 million residents that produces 15 percent of the nation’s food, an area stretching from Wyoming, Utah, Colorado and New Mexico to Arizona, Nevada and Southern California.

Water levels in the nation’s largest reservoir, Lake Mead, located on the Colorado River in Nevada, have been falling for some time. Similarly, there is a strong chance that this year, for the first time, the water supply from Lake Powell, 180 miles upriver and straddling the border of Utah and Arizona, will be curtailed. That could begin a wave of rationing that would lead to significant political conflict among the states, particularly between Arizona and California.

The great paradox is that as we face these severe shortages of water, an equally dangerous threat is posed by too much of it, mainly from rising sea levels. For a vivid example, just look at what is happening in Key West and Miami right now -- knee-high water in the streets even in pleasant weather. Sea levels in Key West have risen an estimated nine inches during the past century, and the increase is projected to continue. With more than 8,400 miles of coastal shoreline and three-quarters of the state’s population living in coastal counties, Florida faces a serious problem.

So does New York City. My brother lives on the Lower West Side of Manhattan, near the Hudson River. During Hurricane Sandy, his building’s basement was completely flooded and the entire power system was destroyed. The Union of Concerned Scientists released a report in May listing national landmarks that are at risk from rising water levels and the results of drought. The Statue of Liberty, just down the river from my brother’s apartment, was the most eye-catching on the list, but others included the Kennedy Space Center, the Jamestown Colony in Virginia and a number of national parks.

Why is this happening? Clearly, climate plays a major role, as does population growth, increased use of water for irrigation and other more urban uses. If we knew the precise reason, it would be a lot easier to find solutions. But the answer is complicated. To know that we are in trouble, you only have to plod through the list of recent reports from the United Nations’ Intergovernmental Panel on Climate Change; the World Bank; the U.S. Environmental Protection Agency; the National Intelligence Estimate; and the U.S. military through the Center for Naval Analyses Military Advisory Board, which reported that the accelerating rate of climate change poses a serious threat to political stability around the world.

They all are saying the same thing: Climate change is one of the major causes of water shortages or excesses, and we no longer can ignore it. What we face is perhaps the greatest of the intergovernmental and international challenges of our lifetimes. Governments -- from small towns and counties to states and provinces to national agencies to international forums -- are going to have to figure this out, because there’s no more time to waste.

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Peter Harkness, founder and publisher emeritus of GOVERNING, now serves as a co-writer of the Potomac Chronicle column. He launched GOVERNING in 1987 after serving as editor and deputy publisher of the Congressional Quarterly news service.